This section provides background information related to the present disclosure and is not necessarily prior art.
Heat-pump systems and other working fluid circulation systems include a fluid circuit having an outdoor heat exchanger, an indoor heat exchanger, an expansion device disposed between the indoor and outdoor heat exchangers, and one or more compressors circulating a working fluid (e.g., refrigerant or carbon dioxide) between the indoor and outdoor heat exchangers. Efficient and reliable operation of the compressors is desirable to ensure that the heat-pump system in which the compressors are installed is capable of effectively and efficiently providing a cooling and/or heating effect on demand.